External HDD powers down too fast

I've got an external USB hard drive that wants to power down very quickly after it is unused. It's in this StarTech enclosure. I haven't timed it, but I'd say it's somewhere between 2 and 5 minutes. I've had the drive for a while now, and it always seemed to follow what I had set in the power options setting in control panel. I've got the "Turn hard disk off after..." setting in power management set to 60 minutes. I also set the "USB selective suspend setting" to disable to see if that had any effect, and it hasn't. I'd like the drive to give me more time before turning itself off, as it gets annoying having to wait for it to spin up if I don't use it for a couple minutes.

I did recently upgrade to Windows 8.1, but I can't say if this happened specifically in conjunction with that, I just know it didn't use to happen in the past. Any ideas on other causes, or any way to set the setting specifically?

This is a problem with Windows 8.1 that is known but isn't being widely reported on. Currently, Microsoft's only fix actually made the problem in a lot of cases worse, and doesn't seem to have made it better for anyone. See this thread here for the gory details:

I've a Media Bridge 4-bay enclosure that was at one point turning off the drives after 10 mins of inactivity, regardless of OS settings, then sometime between Win 8 and 8.1, it went to NEVER turning them off.